This invention relates generally to an overlay device utilized in conjunction with an illuminated transparency viewer for holding a plurality of relatively rigid transparencies, such as photographic slides, in viewing position.
Illuminated transparency viewers, or light boxes, commonly have a light source for providing a strong uniform light on a translucent surface to enable negatives, transparencies, slides and the like to be conveniently examined. Typically such viewers are employed for editing or sorting and sequencing of such transparencies and slides.
When the viewer is mounted to provide a vertical or near vertical viewing surface, slides cannot easily be sorted or viewed without providing some means for holding them in position. In the prior art, overlay devices have been disigned which are adapted to overlie the viewing surface and provide support for the slides. Such overlays have been formed from a sheet translucent material having a sawtooth section so as to provide a series of shelves or ledges on which the edge of the slide may be placed. The slides are then tilted rearwardly so as to rest against the translucent sheet.
Other overlays have been constructed to provide a grid of parallel bars spaced apart at a distance slightly less than the height of the slides. Each bar has a channel into which the bottom of the slide may be inserted with the top of the slide resting against the forward edge of the bar above. The above-described overlays are useful for sorting, but cannot be used to transport or store slides which the user is sorting, but wishes to put aside, since the slides are easily dislodged from their overlay locations.
Overlays have been developed which permit sorting and also provide means for retaining the slides therein for storage. One such overlay provides individual pockets for each slide. One grid-type overlay utilizes bars which have grooves or channels at both top and bottom. The slides are inserted between adjacent bars so that the bottom edge of the slide is in the top channel of the lower bar and the top edge of the slide is in the bottom channel of the upper bar. To avoid the necessity of bending or flexing the slides to place them in the grid, the bars are somewhat flexible so that they may be forcefully deflected away from each other during insertion. However, when the overlay is filled with slides, insertion or withdrawal of selected slides is difficult without disturbing the remaining slides placed in the overlay. In addition, the slides may slip from side to side within the overlay when the overlay is moved.